Electric-current regulator



July 1 1924. 1.500,082

w. LANGD'ON-DAVIES ET AL ELECTRIC CURRENT REGULATOR I I the PatentedJuly 1, 1924.

UNITED STATES WALTER LANGDON-DAVIE-S AND ALFRED SOAQVIES, OF LONDON,ENGLAND.

ELECTRIC-CURRENT REGULATOR.

Application filed February 27, 1922.

To all whom it may concern:

Be it known that we, WALTER LANGDON- DAVIES and ALFRED SOAMES, subjectsof the King of England, and both residing at London, in England, haveinvented certain new and useful Improvements in Electric- CurrentRegulators of which the following is a specification.

This invention relates to electric current regulators particularlysuitable for use in alternating current circuits and has specialreference to regulator's which comprise two relatively movable mutallyinductive circuits in which the automatic relative movement varies thechoking effect on the circuit or alters the, ratio of transformationthuscontrolling the'voltage or current in the working circuit.

The specification of our application for United States Letters PatentSerial No. 309,27 9 describes a construction of regulator of thisgeneral type in which the two mutually inductive circuits are in theform of coils wound upon magnetisable cores arranged so that althoughone coil and its core can rotate partially relatively to the other, thereluctance of the magnetisable circuit remains substantially constant.The rotation of the movable coil and its core is in this. previousconstruction so controlled that those members remain stationary untilthe current reaches a predetermined value and then move into such aposition as to keep the current constant.

The regulator according to the present invention may be of similiarconstruction so far as the coils and their cores are concerned but thecontrol is different for it is found in practice that in certaincircumstances, for instance in arc welding, less mechanical control isadvantageous in the initial position of the regulator provided that themaximum movement of the movable coil is limited.

Therefore according to the present invention, a stop or similiar deviceis provided which will prevent the regulating action from proceedingbeyond a definite amount. This limit is preferably variable in order tosuit the working conditions and such variability may be secured byprovid ing s'ay'a' series ofhol'e's in any one of which a stop may beplaced to prevent further movement of the movable coil. Thus as movablemember moves from its 7 original position, it introduces impedanceSerial No. 539,568.

- or otherwise controls the current in the working circuit until itreaches the stop. In this position the impedance in the circuit will bethat most suitable for the workmg conditions, and under normal workingconditions the regulator will remain at or about this position. It willbe understood that if an operation such as arc welding is being carriedon, the action of the regulator at its limited maximum position will besuch that no very bad effect will be obtained even if the workingcircuit is sho'rt-circuited.

The provision of this stop whose position is preferably variable, is anessential feature of the present invention but it is convenient tofurnish the regulator also with some device which will act to preventits movement being too sudden. Such a device may be a dash pot or itsequivalent and in some cases it may be arranged to act strongly in onedirection only. It is however to be understood that this one wayretarding device is not essential to the present invention and that insome cases no separate retarding device need be used, the inertia of themoving parts thems lves being suficient.

The improved regulator is conveniently provided with some means forbringing the movable part back to its original position. Thisarrangement may be a light spring or weighted arm exercising suiiicientforce for its purpose but not primarily or necessarily acting to anextent su'flicient to keep the. current constant after the movement ofthe regulator has started.

As above mentioned the general construction of the improved regulatorapart from its controlling arrangements may be similar to that describedin our prior specification Serial No. 309,27 9, the relative movement ofthe two coils being rotary and the magnetic circuits such that thereluctance remains substantially constant. The windings may act as atransformer or as a choke coil.

In addition to the arrangement of coils mentioned in that priorspecification, al ternative arrangements are possible. In one suchalternative, instead of the two coils being in series as in the exampleshown in Figures 2 and 4e of the drawings accompanying our priorspecification Serial No. 309,279, the working circuit may include onecoil only, and the other coil may be a winding' short-'circuited onitself.

In the. other alternative although the two coils may be in series Withthe working circuit, they may have an unequal number of turns. Theeffect of this is to introduce a certain amount ofchokes or impedanceinto the circuit independent of the position of the regulator. Suchindependent choking effect if required, may however be introduced byinserting a separate impedance in another part of the circuit.

In the accompanying drawings,

Figure 1 is a perspective view showing one construction of regulatoraccording to this invention,

Figure 2 is a similar view with the cover removed,

Figure 3 is a diagram showing the electrical circuit of the regulator.

For the sake of clearness it is convenient first to refer to Figure 3which shows the two magnetisable cores A and B provided with windings Cand D after the manner of the stator and rotor of an induction motor.The general arrangement of the cores and their coils is similar to thatdescribed in the specification of our application for United StatesLetters Patent Serial'No. 309,279.

On the shaft B (Figure 2) of the rotor member B is mounted a pinion Ethe teeth of which engage with those of a quadrant on a lever F pivotedas at F to afixed arm or bracket G. To the free end of the pivoted leverF is pivoted a link or connect ing rod H joined at its lower end to theplunger J of a dash pot J.

The initial position of the regulator is determined by a stop K (Figures1 and 3) against which restsan arm L attached to the shaft B. In thediagram forming Figure 3, the stop K is shown in such a position that.the rotor B and its coil '1) are given a slight lead relatively to thestator and its winding so that in operation the rotor will tend to turnin a counter-clockwise direction. The amount of this lead may be variedby moving the stop K which as shown in Figure 1 may be in the form of astud which can be shifted in a curved slot M in the cover M. Only acomparatively' light controlling force is required which in theconstruction shown in Figures 1 and 2 is provided by a spring N havingone end fixed and the other attached to a small pulley B on the rotorshaft B.

The amount of rotation of the rotor memher is limited by a stop 0 theposition of which may be varied as indicated for instance at the threeplaces marked on Figure 3. In practice the stop is conveniently in theform of a stud and hand wheel nut which can be moved to any desiredposition in the slot M as shown in Figure 1. i

In Figure 3 the two windings C and D are shown joined in series in theworking circuit which by way of example is illus trated as arranged forelectric welding. In

the initial position the amount of impedance or choking effect is slightfor the magnetisation of the iron circuit produced by the one coil ispractically neutralised by the other coil, the only efi'ective flux,supposing the number of turns in the two coils to' be equal, being dueto the slight lead given to the rotor. When the current is switched onthe rotor turns in a counterclockwise direction but its movement isprevented from being too sudden by the dash pot J. As it turns thechoking effect gradually increases until further movement of the rotoris prevented by the arm L coming into contact with the stop 0 whoseposition has been arranged so that the choking efi'ect in that positionis most suitable for the conditions under which the regulator isworking.

It is sometimes desirable to arrange for the return movement of therotor member to be as free as possible and this can be done for instanceby providing some known form of valve indicated diagrammatically at J inFigure 2 inthe plunger J of the dash pot. V

It is to be understood that the'mechanical details of the constructionshown in Figures l and 2 are given by way of example and that they maybe varied without departing from the spirit of this invention.

l/Vhat we claim as our invention and desire to secure by Letters Patentis 1. In an automatic regulator for alternating current arc weldingcircuits, in combination, a stationary magnetizable core, a secondmagnetizable core partially rotatable relative to the fixed core withoutaltering the reluctance of the magnetic circuit, a winding on each core,said windings being in inductive relationship with each other andconnected in the welding circuit, an arm on the rotatable core, anadjustable stop in the path of motion of said arm and means forpreventing rapid movement of the arm in the direction of said stop, butallowing it quick return.

2. In an automatic regulator for alternating current arc weldingcircuits, in combination, a pair of relatively rotatable magnetizablecores, a winding on each core connected in the welding circuit,adjustable means for setting the amount of lead, an adjustable stop fordetenninmg the amount of relative rotation, means for retarding therotation in one direction but assuring rapid rotation in the otherdirection.

3. An automatic regulator for an alternating electric current circuitcomprising in combination, a stationary magnetisable core, a windingthereon, a second magnetisable core partially rotatable relatively tothe fixed core without altering the reluctance of the magneticcircuit, awinding on the partially rotatable core in inductive tel?" tionship withthe Winding on the fixed core, an arm moving with the partiallyrotatable core, an adjustable stop in the path of motion of said arm, apinion rotating With 5 the partially rotatable core, a dash pot, a

plunger for said dash pot connected to the WALTER LANGDON-DAVIES. pinionby means of a pivoted toothed quad- ALFRED SOAMES.

rant, and a valve in said plunger to allow for its quick returnmovement.

In testimony whereof We have signed our 0 names to this specification.

